3120,?, 122, 23, 4

As per above given series , we can see that
Descending order of given series -
Next term = ( 5 x previous term ) + odd number ( which starts 3 )
Here , 5th term = 4
4th term = 5 × 5th term + 3
⇒ 4th term = 5 × 4 + 3 = 23
3rd term= 5 × 4th term + 7
⇒ 3rd term= 5 × 23 + 7 = 122
Similarly , we can find all others terms also.
2nd term = 5 × 3rd term + 11
⇒ 2nd term = 5 × 122 + 11 = ?
⇒ ? = 621
1st term = 5 × 2nd term + 15
⇒ 1st term = 5 × 621 + 15 =3120